From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id C1A941A09A7 for ; Sat, 14 Nov 2015 02:58:27 +1100 (AEDT) Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 13 Nov 2015 08:58:25 -0700 Received: from b03cxnp07028.gho.boulder.ibm.com (b03cxnp07028.gho.boulder.ibm.com [9.17.130.15]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id 598E03E4003F for ; Fri, 13 Nov 2015 08:58:21 -0700 (MST) Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by b03cxnp07028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id tADFsqoW9568628 for ; Fri, 13 Nov 2015 08:54:52 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id tADFwKUl030813 for ; Fri, 13 Nov 2015 08:58:21 -0700 Subject: Re: [xmon PATCH 1/1] RFC: Add xmon command to dump process/task similar to ps(1) To: Benjamin Herrenschmidt , linuxppc-dev@lists.ozlabs.org References: <56420DC2.3070500@linux.vnet.ibm.com> <56422051.8030505@linux.vnet.ibm.com> <1447229393.31884.152.camel@kernel.crashing.org> From: Douglas Miller Message-ID: <5646089B.6090408@linux.vnet.ibm.com> Date: Fri, 13 Nov 2015 09:58:19 -0600 MIME-Version: 1.0 In-Reply-To: <1447229393.31884.152.camel@kernel.crashing.org> Content-Type: multipart/mixed; boundary="------------010909050307000501010903" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This is a multi-part message in MIME format. --------------010909050307000501010903 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Thanks, Ben, for the feedback. Here is an updated patch. I added a macro XMON_PROTECT() to wrap a statement in what I think is the correct setjmp/protection code. Each place seems to do it slightly differently, so I wasn't sure what the right way was and didn't want to change all other places until we were certain. If you have a better way to implement this, please let me know. It may be difficult to make a macro that fits all use cases, too. I checked using a task point of NULL and it errored out safely, and also tried a pointer to valid memory but not a valid task_struct and it also errored out cleanly. Of course, random memory might not always cause a fault but rather just print garbage. Thanks, Doug On 11/11/2015 02:09 AM, Benjamin Herrenschmidt wrote: > On Tue, 2015-11-10 at 10:50 -0600, Douglas Miller wrote: >> +{ >> + unsigned long tskv; >> + struct task_struct *tsk; >> + >> + if (scanhex(&tskv)) { >> + procshow((struct task_struct *)tskv); >> + } else { >> + for_each_process(tsk) { >> + procshow(tsk); >> + } >> + } >> +} >> + > The main thing is wrap it with the setjump magic that xmon uses for > other things that allows it to recover if you hit a bad pointer > along the way: > > if (setjmp(bus_error_jmp) == 0) { > catch_memory_errors = 1; > sync(); > ... do your stuff... > sync(); > } > catch_memory_errors = 0; > > We could make some kind of helper or macro to factor that out > while it it ;-) (For bonus points !) > > Cheers, > Ben. > > --------------010909050307000501010903 Content-Type: text/x-patch; name="0001-Add-xmon-command-to-dump-process-task-similar-to-ps-.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename*0="0001-Add-xmon-command-to-dump-process-task-similar-to-ps-.pa"; filename*1="tch" >>From a0e7eeef8c51ecedad131aa4c04541f37fc083c4 Mon Sep 17 00:00:00 2001 From: Douglas Miller Date: Thu, 5 Nov 2015 07:55:33 -0600 Subject: [PATCH] Add xmon command to dump process/task similar to ps(1) --- arch/powerpc/xmon/xmon.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 58 insertions(+), 0 deletions(-) diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 13c6e20..5c24f55 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -149,6 +149,7 @@ static int cpu_cmd(void); static void csum(void); static void bootcmds(void); static void proccall(void); +static void proclist(void); void dump_segments(void); static void symbol_lookup(void); static void xmon_show_stack(unsigned long sp, unsigned long lr, @@ -191,6 +192,24 @@ extern void xmon_leave(void); || ('A' <= (c) && (c) <= 'Z')) #define isspace(c) (c == ' ' || c == '\t' || c == 10 || c == 13 || c == 0) +/* + * Wrap a statement (typically function call) in setjmp to + * protect it from memory access errors. msg... are printf + * fmt+args used if error is trapped. + */ +#define XMON_PROTECT(stmt, msg...) \ + if (setjmp(bus_error_jmp) != 0) { \ + catch_memory_errors = 0; \ + printf(msg); \ + } else { \ + catch_memory_errors = 1; \ + sync(); \ + stmt; \ + sync(); \ + __delay(200); \ + catch_memory_errors = 0; \ + } + static char *help_string = "\ Commands:\n\ b show breakpoints\n\ @@ -228,6 +247,7 @@ Commands:\n\ mz zero a block of memory\n\ mi show information about memory allocation\n\ p call a procedure\n\ + P list processes/tasks\n\ r print registers\n\ s single step\n" #ifdef CONFIG_SPU_BASE @@ -947,6 +967,9 @@ cmds(struct pt_regs *excp) case 'p': proccall(); break; + case 'P': + proclist(); + break; #ifdef CONFIG_PPC_STD_MMU case 'u': dump_segments(); @@ -2450,6 +2473,41 @@ memzcan(void) printf("%.8x\n", a - mskip); } +static void procshow(struct task_struct *tsk) +{ + char state; + + state = (tsk->state == 0) ? 'R' : + (tsk->state < 0) ? 'U' : + (tsk->state & TASK_UNINTERRUPTIBLE) ? 'D' : + (tsk->state & TASK_STOPPED) ? 'T' : + (tsk->state & TASK_TRACED) ? 'C' : + (tsk->exit_state & EXIT_ZOMBIE) ? 'Z' : + (tsk->exit_state & EXIT_DEAD) ? 'E' : + (tsk->state & TASK_INTERRUPTIBLE) ? 'S' : '?'; + + printf("%p %016lx %6d %6d %c %2d %s\n", tsk, + tsk->thread.ksp, + tsk->pid, tsk->parent->pid, + state, task_thread_info(tsk)->cpu, + tsk->comm); +} + +static void proclist(void) +{ + unsigned long tskv; + struct task_struct *tsk; + + if (scanhex(&tskv)) { + tsk = (struct task_struct *)tskv; + XMON_PROTECT(procshow(tsk), "*** Error dumping task %p\n", tsk); + } else { + for_each_process(tsk) { + XMON_PROTECT(procshow(tsk), "*** Error dumping task %p\n", tsk); + } + } +} + static void proccall(void) { unsigned long args[8]; -- 1.7.1 --------------010909050307000501010903--